The present invention is directed generally to an improvement for reducing the fuel consumption of conventional forced-air heating systems and more particularly to an auxiliary firebox-heated boiler including a heat exchanger in the cold air return of a forced-air heating system for pre-heating the air being fed through the conventional furnace.
In conventional forced-air systems, the furnace unit requires expensive natural gas or electricity for heating air which is forced by blowers through hot air ducts to a space to be heated. At the same time, cool air is drawn into the furnace through cold air ducts which are also in communication with the space to be heated. Boilers have previously been provided in communication with heat exchangers in the cold air duct for pre-heating air introduced to the main furnace but little if any advantage is gained by such a boiler which itself requires gas or electricity for heating the water therein.
Accordingly, it is a primary object of the present invention to provide in combination with a conventional forced-air heating system, an auxiliary boiler/heat exchanger combination wherein the boiler is adapted to be fueled with relatively inexpensive combustible materials such as wood, coal and the like.
Another object is to provide in such combination, an improved boiler having a firebox extended into and substantially surrounded by the tank portion thereof.
Another object is to provide such a boiler including a flue directed upwardly from the firebox through the tank thereby providing additional surface area for heating fluid in the boiler tank.
Another object is to provide such a boiler wherein heating tubes in communication with fluid in the boiler tank extend through the firebox at a position for supporting combustible material.
Another object is to provide a forced-air heating system equipped with an auxiliary firebox-heated boiler, which system is adapted to first rely on the boiler to supply heat and secondarily rely on the conventional furnace only when the heating requirements exceed boiler capability.
These and other objects of the invention will be apparent to those skilled in the art from the following summary and description.